Printing machines normally include a printing couple or head which has a number of cylinders and/or rollers such as impression cylinders, master or plate cylinders, blanket cylinders, ductor rollers, transfer rollers, oscillating rollers, form rollers, and the like. For instance, an ink fountain is disposed generally at the rear of the machine for feeding ink to the various rollers of the printing couple which transfers images to copy sheets. In such printing machines as multi-color offset perfecting and nonperfecting web and sheet fed presses, a moisture fountain also is disposed adjacent the printing couple for feeding moisture to the printing couple. A number of rollers which generally can be termed "distribution" rollers are provided between the ink fountain and/or moisture fountain for distributing ink and/or moisture to the printing couple of the machine.
One of the problems with ink feeding systems in machines of the character described above is the inability to effectively compensate for varying environmental conditions, such as varying temperature and/or humidity. It has been found that moisture content or "presence" in the immediate environment of a printing or duplicating machine may be for the biggest problem area in maintaining quality printing. For instance, too much moisture in an inking system can "flood" the ink and cause emulsification. Even a 0.5-1.0 percent change in humidity can have a significant change in the ink flow characteristics of the machine. Consequently, an operator is constantly adjusting the ink fountain and/or moisture fountain of the machine in varying environmental conditions, because controlling the environmental humidity is very difficult if not impossible in a particular location. Yet, moisture control cannot be divorced from temperature control within the printing unit.
The moisture problem, above, in conjunction with the need for ink/water balance in conventional offset lithography has traditionally been the source of a multitude of problems for the offset printer. Variations in ink/water balance can cause emulsification of ink, as stated above, and can also lead to inconsistency in color, longer drying times, streaking problems as well as scumming and plugging of halftones. These variables include such things as water hardness, PH, conductivity, alcohol content, water take-up of ink and absorption of substrates.
Because of the various problems identified above, there is a definite contemporaneous trend to "waterless" printing processes and/or temperature control systems for the individual printing units in the printing process. By eliminating the need for ink/water balance, the waterless system changes the printing process from a chemical/physical process to a purely physical one, eliminating a large percentage of process variables as described above. The waterless system offers a shorter learning curve for press operators and greater ease of operation. Because there is no need to achieve ink/water balance at the start of a press run, a waterless press can roll up to color almost immediately. The system will normally achieve color in less than twenty impressions, thus giving the press operator nearly instant color communication. Response times to color changes are dramatically improved over conventional lithography. Controlling the water temperature of the individual printing units gives greater control of the printing process.
A control system to maintain the proper temperature is required for a waterless printing process. The control system normally includes a water circulation system through one or more points of the printing unit such as the plate cylinder, the vibrator roller(s) or the ink "ball" roller of the printing unit. A popular temperature control system circulates the water through one or more of the ink distribution rollers of the machine, such as an oscillating or vibrator roller. The system also includes water heater and chiller units, pumps, valving and appropriate conduits or piping. A temperature monitoring system is incorporated in the printing unit, such as at the plate cylinder surface, and a feedback system is provided to control the plate cylinder surface temperature by adjusting either water temperature or water flow to the vibrator roller(s). The bulk of the water circulation system, such as the water heater and chiller units, pumps, valving and the like normally are housed remote from the printing machine itself.
Because of the remoteness of the control unit, a water distribution system is required between the remote control unit and the ink distribution rollers of the machine through which the water is circulated. Heretofore, the water distribution systems of the prior art have included hard metal conduits or pipes, such as of copper material or the like. Such hard metal piping is not very cost effective, particularly in installation costs, which include many straight pipe pieces, elbows, junctures and the like. Cosmetically, such hard metal piping is not aesthetically pleasing at all. Other problems include potential water leakage because of the number of pipe pieces and fittings required between the remote control unit and the printing machine. Such hard metal piping also has a tendency to "sweat" due to differential temperatures between the water within the piping and the temperature of the surrounding environment. All of these problems are magnified in a multi zone control system wherein a plurality of printing machines or a plurality of printing units within a large press, for instance, are controlled from a single control unit which is considerably remote from the machines themselves.
The present invention is directed to solving this myriad of problems by providing a very simple, cost effective and substantially maintenance free water distribution system between a remote control unit of an ink flow temperature control system and one or more printing presses controlled by the system.